Does anyone know if changing the trans or diff fluids out with something like MTL or Synchromax in the trans or Redline shock proof in the diff will void the warranty? Just something I'm considering. The first to help with shifting of course.

 

2 things. maybe 3
only if something happens
only if your dealer is a *****
then again you can always put the stock fluid back in before a service call.

To be honest, the fluid will only help a small amount.
what's your complaint about shifting? if its lock out at high RPM / its the clutch
if your just having a hard time find gears and some notchy feeling then get the BF bracket and call it a day.

 

The biggest reason for changing is track time. I guess I can just use factory fluids. Though I've heard that some fluids have been OK'd so to speak by Ford. Just not finding anything definitive on that.

 

Most dealers will just make sure there is some in there, not do some in depth analysis of what it is.

That said, the factory stuff is actually quite good. DCT in the trans is better than a lot of the supposedly superior aftermarket stuff for smooth shifting. The rear gear fluid is just your standard 75W90 GL5 gear oil, hard to go wrong there but, it is quiet in terms of the Tlok clutches, because of the Ford fish oil.

 

I run Synchromax in the trans. Good stuff. Helps make shifts smoother, but every now and then you still get crunchiness. Also less viscous at lower temps, which is probably why you notice a small improvement in shifting. I heard a lot of people rave about Redline as well.

Use whatever fluid you like. Ford just gives you specs for viscosity of rear dif fluid so that's easy.

 

Nope, not unless there's a problem and they can prove that the fluids you swapped caused the problem. So, just make sure to use the right viscosity and add the friction modifiers as needed.